EUVL, i.e. microlithography at 13nm is one of the most likely technologies to satisfy the requirements for the 45nm-node and below of the IC-manufacturing roadmap The development of the first step and scan machines meeting production requirements of field size and resolution is in progress. A key component of these machines will be a diffraction limited, off-axis mirror system with aspherical surfaces. The optical surfaces of these mirrors have to be fabricated and measured with unprecedented accuracy. In recent years, technology development at Carl Zeiss SMT AG was focussed on the on-axis aspheres of the NA=0.30 micro exposure tool (MET). Presently this technology is transferred to the surfaces of a NA=0.25 off-axis, large field system The current status of the fabrication and metrology of both on-axis and off-axis mirrors will be reviewed.

%675$&7EUVL (extreme ultraviolet lithography), utilizing an actinic wavelength of about 13 nm , appears to be the most promising technology approach to reach the 30 nm node.Calling for diffraction limited imaging performance, EUV demand unprecedented requirements for figure metrology and fabrication technology. This paper gives an overview over problems rising from the interferometric measurement of aspheric EUV mirrors. ,1752'8&7,21The resolution of a optical projection system is given bywhere λ is the wavelength of the radiation used for imaging, and NA is the numerical aperture of the imaging system. k 1 is a process factor. The resolution RES can be increased by decreasing the operation wavelength λ or by increasing the NA of the system. But increasing of the NA is limited due to physical constraints. Beyond this, increasing the NA reduces the depth of focus (DOF) of the system, with k 2 being also a process factor:In the semiconductor manufacturing technology, the DOF determines the process window and is therefore decisive for performance and throughput of the projection system 6 .Assuming an actinic wavelength of λ=13.4 nm, table 1 shows a comparison between EUV-and the contemporary VUV-technology. Obviously, the EUV-technology increases the resolution by a factor of at least 2 without reducing the DOF.1

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